Method of coating condensers.



' fMo 'roiI, SUIlTZlER OE BRooKLYN, NEW YoRK, AssIGNoR T0 WESTERN ELECTRIC ,YoRK. j

i I j 1,210,722; 3 s ecification of LettersIatent.

" ma as,

To all whom, it may concern:

7 Be it known that 'I, MORTON SUL'rznR,a citizen of the United-States, residing at v 'Brooklyn, in the county of Kings and State of New York, have invented certain new and useful Improvements in Methods 'of' Coating Condensers, of which the following Lisafull, clear, concise, a-nd exact descripntion un. I V

fThis inventionjrelates to'"a'method of coating condensers in? order to prevent the.

admission. of moisture and to enable them -.to w thstand rough usage and largevar1atlons 1n temperature.

" .Standardcondensers are-usually manufactured of alternatejplates of tin foil and mica impregnated with a wax, usually parafiin. In order to protect'the finished units from the admission of moisture, they areusually' dipped in paraffin or some such wax. When, 1 however, such' condensers are used 1n telephonecircuits and are exposed to the elements, it has been found that at low tem- .peratures, such" as 10 degrees Fahrenheit, 'the'coating-of. paraffin will crack and fall 7 ofl," leavingthe unit unprotected. Itfis desirable, therefore, to supply a condenser with a more substantial coating, particularly one which isjmore impervious to mois- 'turethanparaflin, and one whichwill withstand climatic variations of temperature.

*The diliiculty, however, with coating such condensers' as describedabove with a more I rugged coating is due to the fact that, if

' {of 120' degrees Fahrenheit or more, it takes thecondenser unit is'raised to a temperature a permanent setand its calibration is there byde'stroyed This results from the fact 1 thatthe melting point of paraifin is in the neighborhood of 120 degrees Fahrenheit.

. A 'compound which has been used eXten sively for coating'and sealing electrical apparatus such as condensers must be raised to a temperature of about '300 or 350 degrees Fahrenheit. As an. illustration of the difficulties encountered in coating standard condensers with such a compound, it may be stated that a. condenser of the above description was dipped in such a molten compound, and it was found that the capaclty ofithe unit had changed about four per cent.

In this invention, Ihave devised a method I i "of treatment whereby a coating of such a pplied to e ectrical apparatus impr gnated {METHOD or COATING coRDEnsERs."

1 coMr n ,{1INooRro ATED, or NEW YO K, N. Y., A. c0RroRA'r-IoN or NEW.

Patented Jan. 2 1917.

Application filed June 24 1916. Serial No. 105,681 7 with such a material as paraflin without seriously affecting the calibration of the apparatus and the method consists essentially in placing. such apparatus impreg- 'nated with. a compound of a low melting point in particular, mica condensers, in a desiccator to remove all traces of moisture.

The desiccator is then placed in a refrigerator and is cooled to a low temperature in Although 'I do not wish to be limited as i paraflin, and which are to be dipped into some suitable compound having a melting point ranging from 300 to 350 degrees, that it is generally sufiici'ent to precool the condensers toa temperature of approximately 10 degrees Fahrenheit.

While this invention has been described specifically in connection with mica condensers, it is apparent that the methodof precooling and dipping is equally applicable to any form of condensers, such as paper condensers, andthat it is also applicable to apparatus other than condensers, such as inductance coils, transformer windings etc, where the conditions to be met with are substantially the same. 7

What is claimed is:

1. The method 'of'coating with a high melting pointcompound, electrical apparatus containing a low, melting point compound, which consists in precooling the apparatus and dipping it in and quickly removing it from the molten compound of high melting point.

2. The method of coating with a high melting point compound, electrical apparatus containing a low melting point compound, which consists in precooling the ap paratus and dipping it in and so quickly removing it from the molten compound that the low melting pointcompound is not permanently afi'ected. V I

3. The method of coating with a high melting point compound, a condenser im- 

